Method and apparatus for removing a pipe from the well



Jan. 4, 1966 R; w. WQ-IANN METHOD AND APPARATUS FOR REMbVING A PIPE FROMTHE WELL Filed Sept. 20, 1960 2 Sheets-Sheet 1 INVENTOR. Rural M nmflJan. 4, 1966 R, W WHANN 3,227,214

METHOD AND APPARATUS FOR REMOYING A PIPE FROM THE WELL Filed Sept. 20,1966 2 Sheets-Sheet z 7 M2 94 /06 M0 I i 1 m8 9/ 4 94 1 ii-i INVENTOR. 990 Rural M Wfiflflfl Z I" 84 I 4/ United States Patent 3,227,214 METHODAND APPARATUS FOR REMOVING r l A PIPE FROM THE WELL Rural W. Whann, 315W. 9th St., Los Angeles, Calif. Filed Sept. 20, 1950, Ser. No. 57,873 11Claims. (Cl. 166-35) This invention relates to a tool for use inseparating a string of pipe in a well above the point at which the pipeis stuck. This application is. a continuation-in-part of my copendingapplication entitled Method and Apparatus for Removing a Pipe From theWell, Serial Number 363,334, filed June 22, 1953, now abandoned.

When a string of pipe becomes stuck in a well and it becomes necessaryto remove at least a portion of the pipe, an operator must determine thelocation of the highest point at which. the pipe is stuck if he is toremove as much of the pipe asipossible. When an operator employs a toolof well-known type for locating the point at which a pipe is stuck in awell, he thereafter removes the locating tool from the well and employsanother tool for separating the pipe above its. stuck point. consumed bythese operations of withdrawing the locating tool from the well andpositioning a pipe separating tool down in the well, the pipe may.become stuck or frozen at a point above that which has been located,whereupon the operator will have to determine the, location of the newstuck point. Thus, he not only loses benefit of the time and efiort hehas already spent, but also he may not be able to salvage or reclaimthat portion of the string of pipe lying below the highest stuck point.This chance that the pipe may become stuck or frozen at a higher pointis especially great dun'ng drilling operation, for, when drilling hasbeen stopped for any reason, the drilling mud used in the drillingoperations may gel or thicken around the stationary drill stem, or afreshly penetrated earth formation may be caused to cave in on the drillstem. It is important therefore, that no time be lost in separating adrill stem above its stuck point and removing it from the well. It isimportant, too, that the pipe separating tool .be positioned adjacent toa point in the pipe which -is known to be free, i.e. above the higheststuck point, when the pipe is being separated, in order to insure thatthe portion of the pipe above the place of separation thereof may bepulled from the well and not be found to be stuck at a higher pointafter it has been separated. As used herein the word pipe refers to adrill stem, a string of casing, a tubing or any other string of pipeemployed in a well. i

The present invention makes itpossible' to separate a pipe in a well ata point thereof which is known to be free at the time of separation, andit is an object of this invention to provide a tool that not onlylocates the highest stuck point and permits an operator to separate thepipe immediatelyabove that point in but a single, trip of the tool intothe Well, but also transmits a signal or indication to the top of thewell that the tool is positioned adjacent to a free point in the pipewhen the pipe is being separated with use of the tool. i It is a furtherobject of the present invention to provide a well tool that may bepositionedat a free point in the pipe immediately above its higheststuck point in a simple and quick operation.

A still further object of the invention is to provide a well tool thatoperates quickly nd efiectively n ep rat ing a stuck pipe at a knownfree point therepf,

Another objec of he invent on s to p ov d pipe separating means that issimple in construction and adapted for use in combination with most anyof the types of stuck point locating tools that are used in welloperations.

There are several known methods for separating a pipe In the time at apoint down in a well. A pipe may be severed as, for example, by beingshot off or cut OE With the use of a jet cut off tool, or the pipe maybe backed off by twisting it in a direction that will unscrew a threadedjoint thereof which connects two sections of the pipe. In the backingoif method of separating a pipe, it is necessary first to jar orotherwise loosen a threaded connection of the pipe, before the pipe canbe unscrewed at that connection. When the pipe connections are formed ofcollars around adjacent ends of the pipe sections, an operator may jarthe collar at the connection to be separated, and in some cases expandthe collar, in order to loosen it. In one form of the present inventionI provide a well tool having means for finding a pipe connection in thefree portion of a pipe above the highest point at which the pipe isstuck in a well, such pipe connection finding means being positioned onthe tool within the limits of means for jarring the located connection,whereby, upon signal that the position of the desired pipe connect-ionhas been located, the said jarring means will be positioned directlyopposite to such pipe connection and the connection may be loosenedwithout further adjustment of the tool in the well.

It is another object of this invention to provide a stuck point locatingtool that operates in response to torque applied to the top of the pipe,and having connection jarring means, whereby the impact of the jarringforce loosens a known free pipe connection while torque is being appliedin a direction tending to unscrew the connection, thus causing the pipeto spin loose when the jarring force is released. i

It is another object of the invention to provide a stuck point locatingtool which carries an explosive separating charge at a position on thetool corresponding tothe position at which it is desired to separate thepipe when the stuck point is found.

Another object of the invention is to provide a method involvingdetermining the lowest free point of a pipe in a well or bore hole andsimultaneously positioning an explosive charge adjacent the free pointwhereby the sepa ration of the pipe can be effected by means of the sametool or instrumentality without further movement thereof after the freepoint has been found.

It is still another object of the invention to provide a locating toolto locate the first free pipe collar above the stuck point and carry ajarring charge to this point whereby the charge is separated from thelocating tool and 'fixed inthe threaded collar joint so that thelocating tool may be moved to a. safe distance above the explosivecharge thereby saving the locating tool.

Another object of the invention is to provide for a continuous andprogressive operation in which time is reduced and the economy of the Opration is raised.

Further objects and advantages of the invention will become apparentfrom the following detailed description taken in connection with thedrawings, which are for illustrative purposes only, wherein:

FIG. 1 is a schematic sectional view showing a pipe which is stuck in aWell, with an embodiment of the nvention positioned therein and shown inelevation with a portion thereof shown in vertical section;

FIG. 2 is a vertical section of the lower portion of an alternative formof the invention;

FIG. 3 is a vertical section of a pgrtion of angther a e n t form 9f t env nt n;

FIQ. 4 is another alternative form of the inventign showing a sideelevation with a portion broken away which the spring fingers arp in algcked inoperative pgsition;

FIG. 5 is a similar view to FIG. 4 but the spring fingers are shown in areleased position;

FIG. 6 is a vertical section of the arrangement shown in FIG. and

FIG. 7 is a sectional view taken on line 7-7 of FIG. 6.

Throughout the drawings, like reference numerals represent like partsthroughout the several illustrated embodiments.

For purposes of simplifying the description hereof, I have chosen todescribe the present invention by reference to the torsion sensing toolillustrated and described in U.S. Letters Patent No. 2,550,964, grantedon May 1, 1951 to Norman Brookes. Referring to FIG. 1 of the drawinghereof, the numeral 10 designates a string of pipe which is stuck in awell 11 at 12. The well tool 15 which I have shown positioned in thepipe 10 is similar in certain parts thereof to the tool shown in thesaid Patent No. 2,550,964, and which operates in response to torqueapplied to the top of the pipe at ground level. The tool 15 comprises apair of pipe engaging members or bow spring cages 16 and 17, spacedapart by the bar 18. The upper cage 16 is rotatably mounted on the bar18 while the lower cage 17 is fixed to the bar.

The tool 15 is lowered into the pipe 10 by means of the cable 19 whichis secured into the cable socket 20 mounted on and rotatable with thetop end of upper cage 16. The cable socket 20 contains certainelectrical elements that are arranged in a known way so as to beactuated in response to relative rotation of the cage 16 and the bar 18.Such electrical elements are connected through conductors inside thecable 19 to electro-responsive indication means at the top of the well,whereby any electrical impulses caused by such electrical elements as aresult of relative rotation of cage 16 and bar 18, will be indicated tothe operator at the top of the well. The details of construction andmode of operation of such electrical elements, electro-responsiveindication means and the circuit therefor, do not constitute the essenceof the present invention, and it is considered suflicient for thepurposes of this description to refer to such elements and means,generally, as those not familiar with the details thereof may refer tothe said Patent No. 2,550,964, for a full and complete description.

In the embodiment shown in FIG. 1, a pipe severing means, designatedgenerally by the numeral 25, is mounted on the bar 18 at a locationbetween the cages 16 and 17. The pipe severing means which isillustrated comprises a shaped charge of explosive material 26 havingsufficient explosive capacity to eut'the pipe 10 off at that portionthereof which surrounds the shaped charge. The shaped charge ofexplosive material 26 is supported between two discs 27 and 28, threadedon opposite ends of a sleeve 29 secured to the bar 18 as with the screws30. A covering 31, of paper or other suitable substance, protects theexplosive material from being damaged. A detonation or blasting cap 32is fitted into a well in the shaped charge through a slot 33 in the disc27 and is electrically connected to the conductors 34 which in turn areconnected to a suitable blasting box 35 at the top of the well. Thewires or conductors 34 may be attached .to the bar 18 as with clips 36or other suitable tying means, and, as is obvious, they may, if desired,be contained within the cable 19.

v In operation, the tool is lowered into the pipe 10 and torque isapplied to twist the pipe, whereby only the free portion thereof, i.e.,that portion above the highest stuck point 12, will be turned while thatportion of the pipe below the stuck point will not turn. Upon applyingtorque to the pipe relative rotation occurs between adjacent annularportions of the pipe throughout its full length above the stuck point.If at the time of applying such torque, the stuck point locating andpipe several tool is positioned above the stuck point 12, the angle ofrotation of the upper cage 16 will be greater than that of the cage 17and bar 18. This occurrence of relative rotation between the elements ofthe tool will be transmitted by the electrical elements andelectro-responsive indication means to the top of the well, and theoperator will know that his tool is positioned above the highest pointatwhich the pipe is stuck. The operator will then further lower the tooland again twist the pipe, repeating these steps until a position isreached where no rotation of the tool occurs. When no relative rotationbetween the cages of the tool has occurred upon twisting of the pipe,the electro-responsivc indication means at the top of the well will bestill and the operator thus knows that his tool is located below thestuck point. He thereupon raises the tool to a location where relativerotation occurs and preferably while torque is still applied to thepipe, he operates the blasting box causing the shaped charge 26 toexplode and sever the pipe at the annular portion surrounding theexplosive, which portion is known to be free at the time of theexplosion. Instead of locating the stuck point by making tests atsuccessively lower points in the free portion of the pipe, the operatormay lower the tool to the bottom of the well and make his tests atsuccessively higher points until he reaches a position where relativerotation occurs between the elements of his tool, whereupon he may cutthe pipe off at that position in the manner described above. Bymaintaining a twist on the pipe and operating the pipe separating meansonly upon indication of relative rotation between the pipe engagingmembers, the operator will know that the pipe is being cut off at apoint above its highest stuck point, and he may proceed to raise thepipe immediately without fear that it has become stuck above the placeof cut off.

In the modification shown in FIG. 2, I provide a means for jarring apipe connection in the free portion of the pipe, and means for findingsuch connection, the connection finding means being arranged within thelimits of the jarring means on the well tool, whereby upon location of apipe connection above the point at which the pipe is stuck, the jarringmeans will be positioned opposite to such pipe connection withoutfurther adjustment of the tool. The connection jarring means in theillustrated embodiment includes the rod 40 which is suspended by the cup41 from the lower end of the bar member 18 below the pipe engagingmember 17. The cup 41 is fastened to the end of the bar member 18 in anysuitable manner, as by the screws 42. Wound around the rod 40 andextending the full length thereof is a string 43 of explosive material,such as, for example, primacord. One end of the explosive cord 43extends into the cup 41 and is knotted around a detonation or blastingcap 44 wired to a blasting box at the top of the well.

The connection finding means of the embodiment shown in FIG. 2 comprisesa tubular member 45 having a plurality of springs 46 circumferentiallysecured thereto. The rod 40 passes through the tubular member 45 andthereby supports the connection finding means. Axial movement of thetubular member 45 with respect to the rod 40 is prevented by means ofthe screws 47. The springs 46 extend outwardly and upwardly from thetubular member 45 and are formed so as to normally extend outwardlybeyond the circumference of the well pipe. In FIG. 2, the string of pipe10 is shown as comprising an upper section 50 and a lower section 51,the adjacent ends of the sections being connected by means of a threadedcollar 53. In practice, the pipe sections do not abut each other, thusleaving a space 54 between the ends of the pipe sections. The springs 46are shown in the drawing as being engaged with the shoulder 55 providedby the end of pipe section 50 in the space 54 between the pipe sections.

In operation the tool shown in FIG. 2 is lowered into the well and asexplained above for operating the tool shown in FIG. 1, the pipe istested at successively lower points until the stuck point is located.The tool is then raised to a position indicating relative rotationbetween the bow spring cages. With torque applied to the pipe inadirectiontending to unscrew the'connection 53, the tool is again raiseduntil the springs 46 snap into the space 5410f the pipe connection andengage the shoulder 55. This action of the springs 46 offers strongresistance to fu'rther'upwa'rd movement of the tool in the well there bysignalling the operator that a pipeconnection has-been located in thefree portion of the pipe. Thus, theexplosive c ord43 becomespositionedcentrally of the pipe connection and upon detonation thereof, it impartsa severe asserts the "pipe coiinection and with the twist that isbeiri'gapplid at'the top at the well, causes the vpipe to spin loose atthat connect-ion. i I

Iii-FIG. 3, the connection finding means and thestring or explosivematerialare shown as beingpositioned between thetwopipeengagingrnembers16 and 17. The sleeve member 58, which corresponds in functionanddesign-to the thbular member 45. shown in FIG. 2, is"secured to thebar 18 in any suitable manner as with'the screws '59. The string or cordof .explosive material 60 is woundlaround the bar 18 and the sleevemembenSS iandiss-ecured tothe bar 18 in any 'suitablefas-hion aswith'the clip -61. As in FIG. 2, the explosive cord is provided at itsupper end with a detonation or blasting cap i63,electricallyconnected-to"ablasting boxat the top of the well. The arrangement shownin FIG. Spositions the explosive string centrally of thefreepi-pe'collar to be 'fj arre dup-on location of such collar above theainter which the pi-peisstuc k. Theexpl osive stringextends beyondthelimits of the oollarifinding means andis preferably actuated while'thecollar is'being strained by 'a fo rcet endingto unsciew it from the topof theweil. It 'seenisobvious, thereforej-that the use of a tool of thetype hereinerbri ve described will iiisu re the operator thereof thatthe pipe connection jarring means is positioned opposite toapipe collarwhichis kn'own to be free and i above the highest stuck poihtof the pipewhen the jarriag' 'ean is actuated.

If desired, the eX-plcsivechar'ge for cuttin'g olfthe well pipemay bepositioned en la trod secured to the lower end otf'the ibar -18,"'in amaniiero'orresponding to that illhsti'atedinFIG;2. Also, itis obviousthat the shaped charge 26 may be constituted of less explosive materialthan required for severing a pipe,whereby it acts to hi'e relyjar athreaded pipe connection. In the case where the' collar jarrihg meanscomprises a shaped charge, as

distinguished from a string or cord of explosive material, thepipeconnection engaging ends-of the connection finding isp'rings are arrangedto'engage a pipe connection within the vertical lirnits ofthe shapedchange, whereby, upon location of a free pipe connection, the jarringmeans will be positioned di'rect'lyoppositeto such pipe connection"without further adjustment of thetool in the Well. It is obvious, r00,thata pipe severing means or a connection jarring means, as herein"described, may be pos-iti-oned,- if desired, on the cable19 above thestuck point locating frriearis of the tool.

From the foregoing it will be observed that in the form ofthe inventionof FIG. 1,"when the stuck point has been fniu'nd, the'exp-l-osive-charge will at that time be vpositioned just above 'it in proper position"for separating the casing.

"No further movemeneor the tool is required, and accordingly;substantial economies "in time and manipulation "of"equipment-areachieved. In theforms of the invention shown in FlGS. 2and3, after the stuck point has been found,"ther'e isonly one furthermovement of the tool,

. 18 respectively. At the lower end of the tubul ar'meimher explosionarea of the jarring charge.

72 there is welded or secured in like manner a cup-like receptaclehaving a bottom 82 and anannularwall 34 projecting upwardly from thecircumferentialedge {of the bottom wa-ll 82. The tubular member 72 iscentrally 1ocated on the bottom wall82 so as to form an annular cavity86 between the inner side of the wall 84 and the lower end 88 ofthetubula'r member 72. The annular cavity 8 5 receivesthe explosivejarring charge 90. A detonation orblast-ing cap 91 is fixed within t-he'jar-ring charge 90 through an opening 101 in the locking plate 96whereby the plate 96 actsin conjunction with-the cup 80 as a supportmeans for the explosive charge 90.

Electrical conductors 93 leading from the cap 91 are wrappedsufficiently around the tubular sleeve 72 so that the well tool may beseparated from the charge 90 and moved upwardlyin the pipe at a safedistance from the explosion.

There are a plurality of equally spaced .s-pring fingers 92circumferentially secured to the side wall 84. At the uppercnds of thesprings 92 there are lip portions 94 which, when in al ocked position asshown inFIG. 4, are securedto the lockingplate 96. The locking plate'96has equally spaced peripheral projections withslots or openings 192toreceive the lip 94 of the spring finger 92. Also shown in FIG. 6 is anactuating means 104 centrallylocated in the tubular sleeves 72 and shownas a solenoid having an armature 166 secured to the locking plate 96 soasto longitudinally move theplate 96 out of engagement with the springfingers 92 causing the fingers to spread and extend into the space 54between the ends of the pipe sections 52 and 51 respectively. In orderfor the'plate '96 to slidably move on the sleeve 72, there have beenformed vertical slots 103 in the lower end 88 of the'sleevemernber 72 toaccommodate matching webs which are in the locking plate 96. Thesolenoid 104 is electrically connected by the conductors 111 which inturn are connected to conductors'112 centrally mounted withinthe well"tool bar 18 passingthroug-h the tool 15 and inside the cable 19 to thetop of the well whereby shearpin 74. The combination of the tool is thenlowered into the well pipe 10 and the sensing device then locates thefirst free collar joint above the stuck point in the well. The tool isthen gradually lifted in anupward direction and in so doing,'thesolenoid is energized releasing the spring fingers 92 so they may engagein the space 54 'between the upper pipe 52and the lower pipe 51'.

Thefingers "92will then engage the lower edge 'of the upper pipe 52, thespring fingers being of such atension as to hold the jarring charge inplace and force the shearing pin to shear at the lower end of the Welltool and thereby leaving the connecting finding means located 'in acentral position at the collar connection, that is, at the plane of thespace 54 between the adjacent ends of the pipes at the selected joint.The well tool continues in an upwand direction unwinding theconductor'93 of the detonationcap "91 to a suflicient length to clearthe well tool from the Although I have shown a solenoid for releasingthe locking plate 96, it can be well understood that the releasingmeansmay be also a mechanical means. Likewise, it can be understood that thedetonation 'capmay also be set off either by a mechanical means or byhaving the separated Well tool taken from the Well and thereafterdropping a weight or a go devil to set off the detonation.

Although the present invention has been illustrated and described withparticular reference to a tool having .bow

*spring' cages for engaging the'inner Wall of the .pipeyand operating inresponse to torsional strain applied to the pipe, the pipe separatingmeans of the present invention may be used in combination with othermeans for locating a point at which a pipe is stuck in a well. Anexample of such other stuck point locating means is illustrated anddescribed in US. Patent No. 2,530,309, granted on November 14, 1950, toPhilip W. Martin. Also, I desire to have it understood that otherconnection finding means may be used instead of the springs 46, such as,for example, any magnetic collar finder, the design and mode ofoperation of which are known to those skilled in the art of well tools;the essence of the present invention being the provision of a free pointlocating tool having means for causing a pipe to be separated at a placetherein which is known to be free and above the highest point at whichthe pipe is stuck, when separation is effected.

I claim:

1. A method for separating a stuck pipe above a stuck point so as tosalvage the free pipe, all in such continuous and rapid progression asto produce a substantially continuous unity of operation which comprisesthe steps of: inserting a combination stuck point measuring tool andexplosive device; locating the stuck point of the pipe; determining theposition of the first free collar joint above the stuck point;positioning an explosive jarring charge at the said joint, whereby thesaid charge may be released to engage said collar joint; holding saidpositioned charge in place with respect to the pipe; separating themeasuring tool from said positioned charge and moving said tool to asafe area above the charge; and discharging said explosive.

2. A method for separating well casings above a stuck point so as tosalvage the freed well casing, all in such continuous and rapidprogression as to produce a substantially continuous unity of operationwhich comprises the steps of: inserting a combination stuck pointlocating and explosive device; locating the stuck point of the pipe;locating said explosive device at a desired free point relative to saidstuck point; engaging the explosive device with the pipe at said desiredpoint; separating the locating device from the explosive device; movingsaid locating device to a safe area in the casing; and discharging theexplosive of said explosive device.

3. Apparatus for locating the stuck point of pipe in a well, locatingexplosive at a joint adjacent thereto, and igniting same to free thejoint, the combination including: stuck point locator means adapted tobe lowered into a well, including means whereby the stuck point of apipe may be located, and including means at the surface of the wellindicating where such stuck point is located; explosive means carried bythe apparatus lowered into the well; means whereby said explosive meansmay be positioned adjacent to a joint in said pipe; there being means,whereby said explosive means is held in position; means permitting saidexplosive means to be separated from the remainder of the apparatuslowered into the well; and means at the surface of the ground wherebysaid explosive may be ignited.

4. Apparatus for locating the stuck point of a pipe in a well, locatingexposive at a joint adjacent thereto, and igniting same to free thejoint, the combination including: stuck point locator means adapted tobe lowered into a well, including means whereby the stuck point of apipe may be located, and including means at the surface of the wellindicating where such stuck point is located; explosive means carried bythe apparatus lowered into the well; means whereby said explosive meansmay be positioned adjacent to a joint in said pipe; means on saidexplosive means to engage said pipe; means permitting said explosivemeans to be separated from the remainder of the apparatus lowered intothe well; and means at the surface of the well operable to fire saidexplosive means while the apparatus is still in the well.

5. Apparatus for locating the stuck point of pipe in a well, locatingexplosive at a joint adjacent thereto, and

8. igniting same to free the joint, the combination including: stuckpoint locator means adapted to be lowered into a well, including meanswhereby the stuck point of a pipe may be located, and including means atthe surface of the well indicating where such stuck point is located;explosive means carried by the apparaus lowered into the well; means forholding said explosive means in a desired position on said pipe; meanspermitting said explosive means to be separated from the remainder ofthe apparatus lowered into the well; and means operable after the stuckpoint of said pipe is located for moving said explosive means to a jointabove said struck point.

6. A method of locating the stuck point of a pipe in a Well and forpromptly removing the free part of said pipe, said method including thesteps of lowering into a well an instrument having stuck pointdetermining means and an explosive, using said instrument to determinethe stuck point of said pipe, locating the exposive at a desiredposition relative to said stuck point and securing said explosive tosaid pipe at said desired position, separating the stuck pointindication means of said tool from said explosive, and igniting saidexplosive while said tool is still in said well.

7. An apparatus for salvanging pipe or casing from a bore holecomprising: a stuck point indicating device adapted to be lowered intothe bore hole and having associated therewith surface apparatus by whichthe stuck point of the pipe is indicated; an explosive carried by saidwell tool; means for locating said explosive at a joint adjacent thestuck point of said pipe and for securing it to said pipe, saidexplosive and other parts of the well tool being separable from eachother whereby said means for locating the stuck point may be removedfrom said explosive; and means operable from the surface of the groundwhereby said explosive may be ignited without removing said indicatingdevice from the well.

8. In a device for facilitating the selection and separation of a pipeat a collar connection comprising: a tubular member for attachment ofmeans for lowering said device into a pipe string; a cup-shapedreceptacle fixed to the lower end of said tubular member; an explosivejarring charge mounted in said receptacle; a plurality of spring fingersfixed on the outer peripheral wall of said receptacle; a locking platemounted for longitudinal movement on said tubular member for lockingsaid spring fingers in an inoperative position, said locking platehaving equally spaced peripheral projections, said projections havingopenings to receive said spring fingers; and an electrically operatedmeans for moving said locking plate out of engagement with said fingerswhereby said fingers may engage in the collar joint of the pipe to beseparated.

9. In a device for facilitating the selection and separation of a pipeat a collar connection, comprising: a tubular member having at its upperend an opening to receive means for lowering said device into a well,the lower end of said tubular member having a plurality of verticalslots; a cup-shaped receptacle fixed to the lower end of said tubularmember; an explosive jarring charge mounted in said receptacle; aplurality of spring fingers fixed on the outer peripheral wall of saidreceptacle; a locking plate mounted for longitudinal movement on saidtubular member for locking said spring fingers in an inoperativeposition, said locking plate having matching webs centrally locatedtherein which are longitudinally moved in said slots in the lowerportion of said tubular member, and equally spaced peripheralprojections with slots to accommodate said spring fingers in aninoperative position; and an electrical means for moving said lockingplate to an unlocked position whereby said spring fingers may engage aselected collar connection in said pipe string.

10. In a device for facilitating the selection and separation of a pipeat a collar connection, comprising: a tubular member for lowering saiddevice into a pipe string; a cup-shaped receptacle fixed to the lowerend of said tubular member; an explosive jarring charge mounted in 9said receptacle; a plurality of spring fingers fixed on the outerperipheral wall of said receptacle; a locking plate mounted forlongitudinal movement on said tubular member for locking said fingers inan inoperative position, said locking plate having equally spacedperipheral projections, said projections having openings to receive saidspring fingers; and remote control means for moving said lock plate outof engagement with said fingers whereby said fingers may engage in theselection of a collar joint of the pipe to be separated.

11. A method for separating a stuck pipe in a Well above a stuck pointso as to salvage the free pipe, all in such a continuous and rapidprogression as to produce substantially continuous unity of operationwhich comprises the steps of: inserting and lowering a tool for locatinga stuck point in a well in combination with an explosive charge;locating the stuck point of the pipe; determining, the position of thefirst free collar joint above the stuck point; engaging an explosivejarring charge to the pipe at said joint; remotely controlled releasingof said change for engagement withsaid first free collar connection;separating the measuring tool from said positioned charge and movingsaid tool to a safe area above the charge; and discharging saidexplosive whereby the free pipe may be separated at the desired pointabove the stuck point. 1 i

References Cited by the Examiner UNITED STATES PATENTS Greene 166-206 XKinley 166*36 McCullough 166-35 Alexander 16'6 36 x Martin 73151 Martin166--35 Brookes 73151 Sweetman 166- 630 X Carlisle 102-20 X Dill 166-1Bender 73--15 1 Bell et a1 166142 X Davis 102-2l.8 X Sweetman 166 63 XSmith 102,-21 X Norman et al 102-20 X Johns 166--63 X CHARLES E.OCONNELL, Primary Examiner. BENJAMIN BENDETI, Examiner.

1. A METHOD FOR SEPARATING A STUCK PIPE ABOVE A STUCK POINT SO AS TOSALVAGE THE FREE PIPE, ALL IN SUCH CONTINUOUS AND RAPID PROGRESSION ASTO PRODUCE A SUBSTANTIALLY CONTINUOUS UNITY OF OPERATION WHICH COMPRISESTHE STEPS OF: INSERTING A COMBINATION STUCK POINT MEASURING TOOL ANDEXPLOSIVE DEVICE; LOCATING THE STUCK POINT OF THE PIPE; DETERMINING THEPOSITION OF THE FIRST FREE COLLAR JOINT ABOVE THE STUCK POINT;POSITIONING AN EXPLOSIVE JARRING CHARGE AT THE SAID JOINT, WHEREBY THESAID CHARGE MAY BE RELEASED TO ENGAGE SAID COLLAR JOINT; HOLDING SAIDPOSITIONED CHARGE IN PLACE WITH RESPECT TO THE PIPE; SEPARATING THEMEASURING TOOL FROM SAID POSITIONED CHARGE AND MOVING SAID TOOL TO ASAFE ABOVE THE CHARGE; AND DISCHARGE SAID EXPLOSIVE.
 3. APPARATUS FORLOCATING THE STUCK POINT OF PIPE IN A WELL, LOCATING EXPLOSIVE AT AJOINT ADJACENT THERETO, AND IGNITING SAME TO FREE THE JOINT, THECOMBINATION INCLUDING: STUCK POINT LOCATOR MEANS ADAPTED TO BE LOWEREDINTO A WELL, INCLUDING MEANS WHEREBY THE STUCK POINT OF A PIPE MAY BELOCATED, AND INCLUDING MEANS AT THE SURFACE OF THE WELL INDICATING WHERESUCH STUCK POINT IS LOCATED; EXPLOSIVE